How many moles of atoms are in 78.4 gram of neon

If 34.2 grams of lithium react with excess water, how many liters of hydrogen gas can be produced at 299 kelvin and 1.21 atmospheres? 2 li (s) + 2 h2o (l) yields 2 lioh (aq) + h2 (g)

Which electron configuration represents the electrons in an atom of sodium in the ground state at stp

Air can be considered a mixture. which statement does not explain why?